1. Field of the Invention
The present invention relates to a two-way telecommunications system comprising a primary station for transmitting messages on a downlink and at least one secondary station for transmitting signals on an uplink and to a secondary station for use in the telecommunications system.
2. Description of the Related Art
For convenience of description the present invention will be described with reference to an acknowledgement back (or back-back) paging system but it can be applied to specific applications of a paging system, for example relaying data to a computer terminal, to cellular and cordless telephone systems and private mobile radio systems.
When a primary station transmits a message which requires a response, even if receipt of the message is acknowledged, perhaps automatically, the primary station has no means of knowing if the message has been read unless a reply has been sent on the uplink. A busy user of a secondary station not only wants to know that he has received a message but also needs to be reminded that the message needs to be answered.
The use of icons to indicate the receipt of messages by a pager and of duplicates of a previously received message is known from U.S. Pat. No. 5,347,269. However once a message has been read by the pager user the relevant icons are no longer displayed. U.S. Pat. No. 5,182,553 discloses a pager which displays a variety of functions as icons. If one of the icons is selected using a cursor, that icon is displayed by inverted video until it is deselected. Finally U.S. Pat. No. 5,552,779 discloses a wrist watch pager in which icons are used to represent common types of paging messages to a user.